Because normal people don’t want to deal with the headaches. Your choices are weird people or intelligence cutouts. (Or abandoning any attempt at privacy in an attempt to be ideologically pure.) Sorry, but those are the options.
Because there are almost no normal people. Everybody's a jerk in private, to somebody, sometime. Everybody's got opinions that half the population doesn't like.
Most people in the world wants some form of ethnic cleansing - that's why you get 'ethnic quarters' in most large cities, people generally like to be around their own 'kind'.
